Green synthesis of functionalized sodalite ZIFs through mechanochemistry and their performance in CO2 capture

Mechanochemical synthesis of Zeolitic imidazolate frameworks (ZIFs) has emerged as a compelling and environmetally conscious alternative to conventional solvothermal methods, especially when they rely on the use of toxic formamide-based solvents and excess of metal precursors or linkers. In this study, a facile liquid assisted grinding synthesis achieving high product yields with short synthesis times, have been introduced for a series of ZIFs with SOD topology featuring both single and mixed ligands with diverse functional groups. The phase pure and crystalline products with even particle size distribution and retained sorption performance confirmed the efficiency of mechanochemical synthesis as sustainable and viable approach for the optimisation and the design of a new ZIF archetypes. Deeper insights into the structural and CO₂ sorption capabilities was gained by a comparative quantum chemical calculations between a benchmark ZIF-8 and a newly synthesized isostructural analogue NICS-23, featuring an ester-functionalized imidazole ligand. The analysis revealed distinctive sorption characteristics of NICS-23, showcasing also its potential for gas separation processes with wet CO₂ involved. Findings highlight the advatages of mechanochemical synthesis in ZIF production as a facile green synthesis method over the longer solvothermal procedure, potentially allowing also for faster screening of functional materials.